Hecticoceras bonarellii
| Hecticoceras bonarellii | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Upper Jurassic (lower Oxfordium ) | ||||||||||||
| 163.5 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Hecticoceras bonarellii | ||||||||||||
| De Loriol , 1898 | ||||||||||||
Hecticoceras bonarellii is a species of the ammonites (Ammonoidea) from the Jura . As macroconches, the animals had a wide-naveled casing with strong ribs and a simple mouth, and as microconches they had bubble-shaped tubercles on the inside of the flanks. The maximum diameter of the species was around 6 cm. The known distribution extended over the area of Western Europe, which was then covered by a tributary sea of the Tethys . The species was first described in 1898 by Perceval de Loriol .
features
On the macroconch, Hecticoceras bonarellii had a slightly wide-naveled casing with thick turns and relatively strong ribbing, its flanks were flattened. Up to a diameter of 15 mm, the case has a smooth shell, before sickle ribs gradually form. The rounded ribs show a club-like thickening towards the outer bend. The secondary ribs disappear towards the sharp keel of the external side of the housing. The macroconch mouth is simple in shape. With a total diameter of 40 mm, the animals were probably fully grown. The microconch of the species was more naveled, high-mouthed and provided with muzzle ears, and it too had flattened flanks. From 15–20 mm the shell develops slightly curved sickle ribs. The primary ribs were partly formed on the round tubercles typical of the subgenus, in others on the inner flank of the otherwise smooth flanks. Occasionally, microconches also had secondary ribs on the living chamber, which were relatively coarse. With an overall diameter of 26 mm, they were probably fully grown.
stratigraphy
Hecticoceras bonarellii occurs in the mariae zone of the European Oxfordium . It is particularly common there in the scarburgense subzone, but it is also found in the praecordatum subzone. The distribution extended over the area of what is now western Europe.
Taxonomy
The species was first described in 1898 by Perceval de Loriol from the Oxfordium near Châtillon JU , de Loriol described the microconch under the name " H. matheyi ". The specific epithet honors the paleontologist Guido Bonarelli . Hecticoceras bonatellii is placed within Hecticoceras in the subgenus Putealiceras . The representatives of this group are characterized by thick coils and strong ribbing on the macroconches, tubercles on the microconches and a keeled external side.
literature
- Kevin N. Kevin N. Page: Ammonites. In: David M. Martill, John D. Hudson (Eds.): Fossils from Ornatenton and Oxford Clay . A determination atlas. Goldschneck-Verlag, Korb 1994, ISBN 3-926129-17-4 , pp. 117-149.
- Arnold Zeiss: Hecticoceratinae (Ammonoidea jurassica) (= Fossilium Catalogus. 1: Animalia. Ps. 96, ZDB -ID 1187037-0 ). Junk, 's-Gravenhage 1959.